Hi, this is my first post to the group.
I was going to begin a similar project myself. You obviously are much
further along (I just had the thought of such a thing).
I'll be traveling to the Twain Papers in Berkeley this spring to do some
research. Perhaps I might be able to help you with some images that the
Papers might hold of places where Twain was. Let me know.
I'm not sure how far along you are on the project, but it's a great idea.
St. Mary's College of Maryland